Faced with a lawsuit by 15 states, the U.S. Environmental Protection Agency announced this week it would no longer delay the implementation of a rule requiring states to reduce emissions of smog-creating air pollution.

Crafted by the Obama administration in 2015, the regulation calls for states to begin meeting stricter ozone standards as of October 1, 2017, lowering the air pollution limit from 0.075 parts per million to 0.070 ppm. Ground-level ozone, or smog, is created when pollutants from cars, power plants, and other common industrial activities react with sunlight. It can cause respiratory and other health problems. In June, U.S. EPA head Scott Pruitt announced the agency would delay implementation of the new standards by one year.

A new study combining European ice core data and historical records of the infamous Black Death pandemic of 1349-1353 shows metal mining and smelting have polluted the environment for thousands of years, challenging the widespread belief that environmental pollution began with the Industrial Revolution in the 1700s and 1800s.

We all know that washing our hands can keep us from spreading germs and getting sick. But a new Rutgers-New Brunswick study found that cool water removes the same amount of harmful bacteria as hot.

“People need to feel comfortable when they are washing their hands but as far as effectiveness, this study shows us that the temperature of the water used didn’t matter,” said Donald Schaffner, distinguished professor and extension specialist in food science.

Road salt, used in copious helpings each winter to protect them from ice and preserve safe driving conditions, is slowly degrading the concrete they’re made of. Engineers have known for some time that calcium chloride salt, commonly used as deicer, reacts with the calcium hydroxide in concrete to form a chemical byproduct that causes roadways to crumble.

Researchers from the University of Antwerp and KU Leuven have succeeded in developing a process that purifies air and, at the same time, generates power. The device must only be exposed to light in order to function.

Smog from cars and trucks is an expected health hazard in big cities, but researchers from the University of Cincinnati found pollution from truck exhaust on one of the most remote mountain roads in the world.